Production of porous polymers

ABSTRACT

A method of producing a polar, porous polymer comprising polymerizing a monomer mixture comprising: 
     (A) about 2 to about 98 percent by weight of at least one cross-linkable monomer having a plurality of CH 2  ═C&lt; groups and 
     (B) about 98 to about 2 percent by weight of at least one monomer selected from the group consisting of (i) copolymerizable monoethylenically unsaturated monomers and (ii) conjugated diene monomers, about 15 to about 100 percent by weight of the total monomers (A) and (B) being polar monomers, 
     In the presence of an organic medium which does not react with any of monomers (A) and (B), and selected from the group consisting of: 
     (I) a mixed organic liquid consisting essentially of (i) at least one liquid which dissolves at least one homopolymer of monomers (A) and (B) and (ii) at least one liquid which does not dissolve at least one homopolymer of monomers (A) and (B) and (II) (iii) at least one liquid which dissolves at least one homopolymer of monomers (A) and (B) but does not dissolve at least another homopolymer of monomers (A) and (B).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the production of porous polymers. Moreparticularly, it relates to a method of producing porous polymers havingpolar groups, an average pore diameter of about 40 A or more, a highpore volume and high mechanical strength.

2. Description of the Prior Art

Porous resins have a wide range of use as ion exchange resins of highefficiency, adsorbents, stationary phases for chromatography, carriersfor catalysts and immobilized enzymes, etc., due to their high surfacearea, fine pore structure and high rate of mass transfer in the resins.Especially with regard to ion exchange resins having high porosity,there are various advantages such as a high rate of ion exchange with anincrease in the ion diffusion velocity in resins, small swellability andshinkability in contact with a liquid, high regeneration efficiency andhigh resistance to organic materials.

Many prior art references teaching various preparation methods forporous resins. For example, British Pat. Nos. 932,125 and 932,126describe a process for preparing a porous cross-linked copolymer byeffecting suspension polymerization of a monomer mixture in the presenceof a precipitant which is a liquid substantially insoluble in water (a)which dissolves the monomer mixture and (b) which does not swell theproduct copolymer in an amount sufficient to separate the productcopolymer from the monomer phase. In this method, phase separation takesplace when about 40 to 50 percent by weight, based on the total weightof the monomers, of a precipitant is employed, and the pore volumebecomes less than about 50 percent based on the resin as such since thepore volume basically depends upon the relative amount of theprecipitant. Furthermore, when the preparation of porous copolymershaving a high pore volume is attempted, phase separation takes place somuch that the mechanical strength of the product copolymers diminishes.

Japanese Patent Laid Open 71790/1973 describes a method of preparing amacroreticular cross-linked copolymer by copolymerizing a vinyl nitrogenheterocyclic monomer such as a vinylpyridine monomer with a polyvinylaromatic hydrocarbon such as divinylbenzene in the presence of a phaseextender (or an precipitant) in an amount sufficient to cause phaseseparation of the cross-linked copolymer. In this method, the phaseextender may be employed in an amount of about 30 to 150 percent byweight based on the total weight of the monomers employed.

U.S. Pat. No. Re. 27,026 teaches a method of preparing a porous polymerhaving a predetermined porosity by polymerizing a monomer mixture of (a)at least one monomer selected from styrene type monomers, acrylates ormethacrylates and vinyl carboxylates and (b) a cross-linking agent suchas divinylbenzene, diethylene glycol dimethacrylate, etc., in thepresence of a solvent mixture comprising: (a) at least one solvent and(b) at least one non-solvent, said solvent mixture having a solubilityparameter chosen within the range δ = δ₀ ± 0.8, where δ is thesolubility parameter of the polymer and δ₀ is the solubility parameterof the polymer, to control the average pore size of the polymer.

British Pat. No. 1,274,361 describes a process for the production ofporous resins by copolymerizing at least one monovinyl compound with atleast one polyvinyl compound in the presence of: (a) at least onenon-swelling adjuvant which dissolves the monomers but neither dissolvesnor swells the polymers and (b) at least one swelling adjuvant whichdissolves the monomers but only swells the polymer without dissolvingthem.

German Patent Laid Open 2121448 describes a suspension copolymerizationin water of an ethylenically unsaturated monomer with a copolymerizablecross linking monomer in the presence of a mixed organic liquid composedof: (a) a component which solvates the copolymer such as an aromatichydrocarbon and (b) a precipitating component for the copolymer such asan aliphatic hydrocarbon.

According to the latter three methods, porous resins having amicroporous structure and a high pore volume can be produced by carryingout the polymerization in a large amount of appropriately chosen organicliquids. These methods, however, can be employed only when thepolarities of the monomers employed are similar each other. For example,according to U.S. Pat. No. Re. 27,026 the solubility parameter for thepolymers to be prepared is in the range of from about 8.8 to about 9.7(cal/ml)^(1/2). However, when a part of the monomers employed is a polarmonomer, the polarity of the copolymer product varies to a great extent,even if the amount of the polar monomer is comparatively small, and thedetermination of a suitable solvent system is often difficult.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a method of producing a porouspolymer having polar groups, an average pore diameter of about 40 A ormore, a high pore volume and high mechanical strength which overcomesthe above drawbacks, i.e., a method of producing a polar, porous polymercomprising polymerizing a monomer mixture comprising:

(A) about 2 to about 98 percent by weight of at least one cross-linkablemonomer having a plurality of CH₂ ═C< groups and

(b) about 98 to about 2 percent by weight of at least one monomerselected from the group consisting of (i) copolymerizablemonoethylenically unsaturated monomers and (ii) conjugated dienemonomers, about 15 to about 100 percent by weight of the total monomers(A) and (B) being polar monomers,

in the presence of an organic medium which does not react with any ofmonomers (A) and (B), and selected from the group consisting of:

(I) a mixed organic liquid consisting essentially of (i) at least oneliquid which dissolves at least one homopolymer of monomers (A) and (B)and (ii) at least one liquid which does not dissolve at least onehomopolymer of monomers (A) and (B) and (II) (iii) at least one liquidwhich dissolves at least one homopolymer of monomers (A) and (B) butdoes not dissolve at least another homopolymer of monomers (A) and (B).

DETAILED DESCRIPTION OF THE INVENTION

In the present invention, the term "polar monomer" denotes a monomerhaving a polar group selected from the group consisting of anitrogen-containing heterocyclic group, nitrile group, amino group,alkylamino group, amido group, nitro group, carbonyl group, aldehydegroup, carbonate group, hydroxy group, carboxyl group, sulfone group andphosphate group. The term "non-polar monomer" denotes a vinylhydrocarbon or a monomer having a non-polar group selected from thegroup consisting of a carboxylic ester group, sulfide group, ether groupand halogen group, but when the vinyl hydrocarbon or monomer has theabove mentioned polar group, the vinyl hydrocarbon or monomer is denoteda "polar monomer". Furthermore, when a monomer has a group other thanthe above mentioned polar or non-polar groups, the monomer having adielectric constant of 7 or more at 20° C is denoted a "polar monomer"and the monomer having a dielectric constant of less than 7 at 20° C isdenoted a "non-polar monomer".

The cross-linkable monomers (A) which may be used in this invention havea plurality of CH₂ ═C< groups, and preferably one to four CH₂ ═C<groups.

Examples of suitable cross-linkable monomers (A) having a plurality ofCH₂ ═C< groups which are polar monomers include divinyldiphenylamine,divinylsulfone, divinylketone, divinylpyridines, divinylquinolines, bis(vinylpyridinoethyl) ethylenediamine, diallyl carbonate, diallyl amine,triallyl amine, triallyl phosphate, N,N'-methylenedimethacrylamide,N,N'-ethylenediacrylamide, N,N'-methylenediacrylamide,1,3,5-triacroylhexahydro-1,3,5-triazine, diallylmelamine and the like.

Examples of suitable cross-linkable monomers (A) having a plurality ofCH₂ ═C< groups which are non-polar monomers include divinylbenzenes,divinyltoluenes, divinylxylenes, divinylnaphthalenes,divinylethylbenzenes, divinylphenanthrenes, trivinylbenzenes,divinylbiphenyles, divinyldiphenylmethanes, divinylbenzyls,divinylphenylethers, divinyldiphenylsulfides, divinylfurans, diallylphthalate, diallyl maleate, diallyl fumarate, diallyl succinate, diallyloxalate, diallyl adipate, diallyl sebacate, diallyl tartrate, triallyltricarballylate, triallyl aconitate, triallyl citrate, ethylene glycoldimethacrylate, triethylene glycol dimethacrylate, polyethylene glycoldimethacrylate, trimethoylolpropane trimethacrylate, pentaerythritoltetramethacrylate, 1,3-butylene glycol diacrylate, 1,6-hexanedioldiacrylate, trimethylpropane triacrylate, pentaerythritol tetracrylate,triallylisocyanurate and the like.

Such cross-linkable monomers (A) can be employed in an amount of from 2to about 98 percent by weight, preferably from about 3 to about 80percent by weight, and more preferably from about 4 to about 60 percentby weight based on the total weight of monomers (A) and (B). When theamount is less than about 2 percent by weight, the resulting porouspolymers swell too remarkably for use.

Examples of suitable copolymerizable monoethylenically unsaturatedmonomers (B) which are polar monomers include dimethylaminoethylmethacrylate, hydroxyethyl methacrylate, hydroxymethylstyrene,N,N-dimethylaminostyrene, nitrostyrene, chloromethylaminostryrene;acrylonitrile and acrylonitrile derivatives such as methacrylonitrilealpha-acetoxyacrylonitrile, alphachloroacrylonitrile, etc.; acrylic acidand methacrylic acid; vinyl ketones such as methyl vnyl ketone, ethylisopropyl ketone, etc.; acrolein; acrylamide and acrylamide derivativessuch as N-butoxymethacrylacrylamide, N-phenylacrylamide,diacetoneacrylamide, N,N-dimethylaminoethylacrylamide, etc.; and vinylnitrogen heterocyclic compounds such as 2-vinylpyrrole, N-vinylpyrrole,N-vinylpyrrolidone, N-vinylsuccineimide, N-vinylphthalimide,N-vinylcarbazole, N-vinylindole, 2-vinylimidazole, 4-vinylimidazole,5-vinylimidazole, 1-vinyl-2-methylimidazole,1-vinyl-2-hydroxymethylimidazole, 1-vinyl-2-hydroxy-ethylimidazole,5-vinylpyrazole, 3-methyl-5-vinylpyrazole, 3-vinylpyrazoline,vinylbenzoxazole, 3-phenyl-5-vinyl-2-isooxazoline, N-vinyloxazolidone,2-vinylthiazole, 2-vinyl-4-methylthiazole, 2-vinyl-4-phenylthiazole,2-vinyl-4-methylthiazole, 2-vinyl-4-phenylthiazole,2-vinyl-4,5-dimethylthiazole, 2-vinylbenzthiazole, 1-vinyltetrazole,2-vinyltetrazole, 2-vinylpyridine, 4-vinylpyridine,2-methyl-5-vinylpyridine, 2-N,N-dimethylamino-4-vinylpyridine,2-vinyl-4,6-dimethyltriazine, 2-vinyl-4,6-diphenyltriazine,isopropenyltriazine, vinylquinoline, etc.

Examples of suitable copolymerizable monoethylenically unsaturatedmonomers (B) which are non-polar monomers include vinyl hydrocarbonssuch as styrene, vinyltoluenes, ethylvinylbenzenes, vinylnaphthalenes,vinylphenanthrenes, vinylmesitylenes, 1-vinyl-2-ethylacetylene, etc.;styrene derivatives such as chlorostyrenes, bromostyrenes,fluorostyrenes, dichlorostyrenes, trifluoromethylstyrenes, etc.;acrylates such as methyl acrylate, lauryl acrylate, chloromethylacrylate, ethylacetoxy acrylate, etc.; methacrylates such as cyclohexylmethacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate,tetrahydrofurfuryl methacrylate, hydroxyethyl methacrylate, etc.;vinylidene compounds such as vinylidene chloride, vinylidene bromide,etc.; vinyl carboxylate such as vinyl acetate, vinyl butyrate, vinylcaprate, etc.; and vinylchloride.

Example of suitable copolymerizable conjugated monomers (B) include1,3-butadiene, isoprene, chloroprene, piperylene, etc.

Such monomers (B) can be employed in an amount of from about 2 to about98 percent by weight based on the total weight of monomers (A) and (B).According to this invention it is required that the monomer mixturecontains about 15 to about 100 percent by weight, and preferably about20 to about 90 percent by weight, based on the total weight of monomers(A) and (B), of polar monomer. When the amount is less than about 15percent by weight, the polarity of the porous polymer product decreasestoo much for practical purposes, and, furthermore, the selection of asuitable organic medium becomes difficult. Also, in the production ofanion exchange resins using vinyl nitrogen heterocyclic compounds whenthe amount is less than about 15 percent by weight, the exchangecapacity as an anion exchange resin becomes too small.

The gist of the present invention is the selection of an appropriateorganic medium.

The guiding principle of selecting an organic medium in the productionof polar, porous polymers according to this invention will now beillustrated.

Since in the polymerization system there is present an organic mediumconsisting essentially of: (i) at least one organic liquid whichdissolves at least one homopolymer of the monomers which are theconstituents of a polymer and (ii) at least one organic liquid whichdoes not dissolve at least one homopolymer of the monomers which are theconstituents of a polymer or (iii) at least one organic liquid whichdissolves at least one homopolymers of the monomers chosen but does notdissolve at least another homopolymer of the monomers chosen, theorganic medium exhibits a middle character between the so-called"precipitant" and "solvent" for the polymer produced. Therefore, phaseseparation slowly takes place in the course of the polymerization. Thus,when an organic medium having a higher solubility for the polymer isemployed, the phase separation mildly takes place and the pore diameterof the resulting polymer becomes smaller. On the other hand, when anorganic medium having a higher precipitancy for the resulting polymer,the phase separation drastically takes place and the pore diameterbecomes greater.

In the production of polar, porous polymers in accordance with thisinvention, firstly, the solubilities of various organic media for eachhomopolymer of the monomers chosen are checked up, and then the organicmedia are classified as follows;

Group (i): organic liquids which dissolve all of the homopolymers of themonomers chosen.

Group (ii): organic liquids which do not dissolve any of thehomopolymers of the monomers chosen.

Group (iii): organic liquids which dissolve at least one homopolymer ofthe monomers chosen but do not dissolve at least another homopolymer ofthe monomers chosen.

In carrying out the present invention, the following five combinationscan typically be employed.

(1) A mixed organic liquid consisting of at least one liquid selectedfrom Group (i) and at least one liquid selected from Group (iii).

(2) A mixed organic liquid consisting of at least one liquid selectedfrom Group (ii) and at least one liquid selected from Group (iii).

(3) A mixed organic liquid consisting of at least two liquids selectedfrom Group (iii).

(4) One liquid selected from Group (iii).

(5) A mixed organic liquid consisting essentially of at least one liquidselected from Group (i) and at least one liquid selected from Group(ii).

Especially when it is necessary to minutely control the pore structureof a polymer, for example, the following method is preferred. Firstly,the polymerization is carried out using an organic medium containing atleast one appropriate liquid selected from Group (iii). When the porediameter of a polymer obtained is smaller than the desired one, the porediameter can be increased by adding at least one liquid selected fromGroup (ii) to the organic medium. Also when the pore diameter is greaterthan the desired one, the pore diameter can be decreased by adding atleast one liquid selected from Group (i) to the organic medium.Especially when an organic medium containing at least two liquidsselected from Group (iii) is employed, the pore diameter can minutely becontrolled. Furthermore, when an organic medium containing at least oneliquid selected from Group (i) and at least one liquid selected fromGroup (ii) is employed, the pore diameter can greatly be varied only byslightly varying the mixing ratio of the liquid from Group (i) to theliquid from Group (ii).

In designing the structure of porous polymers in accordance with thisinvention, the amount of an organic medium in addition to the organicmedium chosen and the mixing ratio of organic liquids becomes animportant factor. That is, the void volume, which means the volume ofthe part excluding the polymer chain in a polymer in the presentinvention, basically increases in proportion to the amount of an organicmedium. Also, the pore volume of a polymer, which means the pore volumeof a polymer having a pore diameter of 40 A or more in the presentinvention depends on the relative amount of an organic medium employedand the pore diameter of a polymer produced. That is, with an increasein the pore diameter the pore volume becomes greater, and with anincrease in the amount of an organic medium the pore diameter and porevolume become greater because phase separation easily takes place.

It is, accordingly, possible to control the pore diameter, void volume,pore volume and surface area of the porous polymers by changing factorssuch as the properties of the organic medium, the amount of the organicmedium employed and the monomers chosen. Furthermore, when a mixedorganic liquid is employed, the pore diameter, void volume, pore volumeand surface area of the porous polymers can be arbitrarily andcontinuously varied by the mixing ratio of the organic liquids.

In the present invention the following method of selecting an organicliquid is employed.

To one organic liquid is added 5 weight percent of one monomer and 0.1weight percent of azobisisobutyronitrile and the resulting solution ispolymerized in a sealed glass tube for about 8 hours at the sametemperature as is to be used for the polymerization reaction of thisinvention, and then the reaction mixture is observed. When the resultingpolymer is precipitated, the organic liquid is denoted an "organicliquid which does not dissolve a homopolymer of the monomer", and whenthe resulting polymer is dissolved in the organic liquid, the organicliquid is denoted an "organic liquid which dissolves a homopolymer ofthe monomer". Also, with regard to one monomer having a plurality of CH₂═C< groups employed as the monomer, when the reaction mixture of theresulting polymer and the organic liquid is opaque, the organic liquidis denoted an "organic liquid which does not dissolve a homopolymer ofthe monomer, and when the reaction mixture is transparent, the organicliquid is denoted an" organic liquid which dissolves a homopolymer ofthe monomer.

For example, the solubilities of some kinds of polymers in organicliquids are described in J. Brandrup and E. H. Immergut, PolymerHandbook, Chap. IV, pages 185 ˜ 234 (1966) and Chap. IV, pages 241 ˜265, Second Edition (1975) which is useful for the selection of solventsand non-solvents.

It is known that the solubility of polymers in organic liquids isevaluated by the relative value of the respective solubility parameters.This method, however, can only be applied to polymers having acomparatively low polarity, and when such a method is applied to thepresent invention which employes a monomer mixture containing at least15 weight percent of a polar monomer, the selection of organic liquidsby solubility parameters often leads to errors.

The organic liquids which may be employed in the present inventiontypically include lower aliphatic alcohols having at most 8 carbon atomssuch as butanols, pentanols, hexanols, cyclohexanol, octanols, etc.;aliphatic or aromatic acid esters such as ethyl acetate, butyl acetates,methyl propionate, ethyl propionate, isobutyl propionates, butyladipates, benzyl acetate, methyl benzoate, ethyl benzoate, dimethylphthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate,etc.; aliphatic ketones such as acetone, methyl ethyl ketone,diisopropyl ketone, methyl isobutyl ketone, diisobutyl ketone,diisobutyl ketone, cyclohexanone, acetophenone, etc.; aliphatic oraromatic nitriles such as propionitrile, n-butyronitrile, benzonitrileetc.; nitroalkanes such as nitroethane, nitropropane, etc.; cyclicethers such as dioxane, dimethyl tetrahydrofuran, etc.; aromatichydrocarbons such as benzene, ethylbenzene, diethylbenzenes, toluene,xylenes, tetraline, etc.; aliphatic hydrocarbons such as hexanes,cyclohexane, heptanes, octanes, decanes, etc.; chlorinated aliphatic oraromatic hydrocarbons such as methylene chloride, tetrachloroethane,chlorobenzene, o-dichlorobenzene, etc. Those skilled in the art,however, will recognize that the organic liquid mentioned are onlyillustrative and that a wide variety of other organic liquids may beequally effective.

Exemplary combinations of monomer mixtures and organic media are shownbelow, where Group (i) denotes organic liquids which dissolve all of thehomopolymers of the monomers chosen; Group (ii) denotes organic liquidswhich do not dissolve any of the homopolymers of the monomers chosen;and Group (iii) denotes organic liquids which dissolve at least onehomopolymer of the monomers chosen but do not dissolve at least anotherhomopolymers chosen.

(I) When a monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes and divinylpyridines, (b) at least onemonomer selected from the group consisting of 2-vinylimidazole,N-vinyl-2-methylimidazole and 4-vinylpyridine, and (c) at least onemonomer selected from the group consisting of styrene,ethylvinylbenzenes, 2-vinylpyridine, 2-methyl-5-vinylpyridine, methylmethacrylate, methyl acrylate and 1,3-butadiene, Group (i) includesacetophenone, cyclohexanone, tetrachloroethane, benzyl alcohol,benzonitrile, nitroethane and nitropropane; Group (ii) includes hexanes,cyclohexane, octanes and decanes; and Group (iii) includes benzene,toluene, xylenes, ethylbenene, diethylbenzene and tetraline, butanols,pentanols, hexanols, cyclohexanol, octanols, ethyl acetate, butylacetates, ethyl propionate, butyl propionates and butyl adipates, methylbenzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate, methylethyl ketone, methyl isobutyl ketone, diisobutyl ketone, chlorobenzeneand o-dichloro-benzene.

(II) When a mononer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, trivinylbenzenes and divinylpyridines,(b) at least one monomer selected from the group consisting of2-vinylpyridine and 2-methyl-5-vinylpyridine and (c) at least onemonomer selected from the group consisting of styrene,ethylvinylbenenes, methyl methacrylate, methyl acrylate and1,3-butadiene; Group (i) includes benzene, toluene, xylenes,cyclohexanone, methyl ethyl ketone, anisole, methyl benzoate, ethylbenzoate, ethyl propionate, dimethyl phthalate, benzonitrile,nitropropane, chlorobenzene and o-dichlorobenzene; Group (ii) includeshexanes, cyclohexane, heptanes and octanes; and Group (iii) includesbutanols, pentanols, hexanols, cyclohexanol and octanols.

(III) When a monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, and divinylpyridines, (b) at least onemonomer selected from the group consisting of styrene,ethylvinylbenzenes, methyl methacrylate, 2-vinylpyridine,2-methyl-5-vinylpyridine and 1,3-butadiene, and (c) at least one monomerselected from the group consisting of acrylonitrile andmethacrylonitrile, Group (ii) includes hexanes, cyclohexane, heptanes,octanes, decanes, pentanols, hexanols, cyclohexanols, octanols; and;Group (iii) includes benzene, toluene, xylenes, ethylbenzene, ethylacetate, methyl propionate, butyl propionates, butyl adipates, methylbenzoate, ethyl benzoate and diethyl phthalate. Furthermore, when onlyacrylonitrile is selected from the above described group (c), Group(iii) additionally includes propionitrile, n-butyronitrile, nitroethane,nitropropane, methyl ethyl ketone, methyl isobutyl ketone andcyclohexanone.

(IV) When a monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes and divinylpyridines, (b) at least onemonomer selected from the group consisting of styrene,ethylvinylbenzenes and 2-methyl-5-vinylpyridine and (c)N-vinylcarbazole, Group (i) includes toluene, xylenes, ethylbenzene,tetraline, dioxane, tetrahydrofuran, chloroform, tetrachloroethane ando-dichlorobenzene; Group (ii) includes hexanes, octanes, hexanols,octanols and cyclohexanol; and Group (iii) includes acetone, methylethyl ketone, methyl isobutyl ketone, dimethyl tetrahydrofuran, ethylacetate and methyl propionate.

(V) When a monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes and divinylpyridines, (b) at least onemonomer selected from the group consisting of styrene,ethylvinylbenzenes, methyl methacrylate and 2-vinylpyridine and (c)N-vinylpyrrolidone, Group (ii) includes hexanes, cyclohexane, heptanesand decanes; and Group (iii) includes ethyl acetate, butyl propionates,benzyl acetate, diisopropyl ketone, benzene, toluene, ethyl benzene andtetraline.

(VI) When a monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of divinylbenzenes andN,N'-ethylene acrylamide, (b) at least one monomer selected from thegroup consisting of styrene, ethylvinylbenzenes, methyl methacrylate andmethyl acrylate and (c) acrylamide, Group (ii) includes butanols,pentanols, hexanols, octanols, cyclohexanol, hexanes, heptanes, octanes,decanes and cyclohexane; and Group (iii) includes benzene, toluene,ethylbenzene, xylenes, tetraline, butyl acetates, ethyl propionate andmethyl benzoate.

The organic medium which may be used in the present invention does notreact any of monomers (A) and (B), and is used in an amount D in percentby weight based on the total weight of monomers (A) and (B) andrepresented by the equation, typically

        about 7 √X < D < about 500 √x,                          

preferably

        about 20 √X < D <  about 200 √X,                        

and more preferably

        about 34 √X  < D <  about 150 √X                        

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).

Thus, when the degree of cross-linking increases, the network structureof the porous polymers becomes denser and it is, accordingly, preferredthat the amount thereof be increased.

The polymerization according to this invention is preferably carried outin the presence of radical initiators. Such radical initiators include,for example, peroxides such as benzoyl peroxide, lauroyl peroxide,di-tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide,cumene hydroperoxide, tert-butyl hydroperoxide; and azo compounds suchas azobisisobutyronitrile, 2,2'-azobis ( 2,4-dimethyl valeronitrile),2-phenylazo- 2,4-dimethyl-4-methoxy valeronitrile and2-cyano-2-propylazoformamide. The amount of the radical initiatorsemployed may vary depending upon factors such as the polymerizationtemperature selected, the organic liquid chosen, the amount of organicliquid employed and other factors. Generally, however, the amount is inthe range of from about 0.01 to about 12 percent by weight based on thetotal weight of monomers (A) and (B). The preferred range is from about0.1 to about 5 percent by weight, and a more preferred range is fromabout 0.2 to about 3 percent by weight. Two or more of these initiatorshaving different decomposition temperatures may also be employed.

Radical polymerization methods by irradiation of light or otherradiation may also be employed in this invention.

The polymerization temperature is typically in the range of about 0° toabout 200° C, a preferred range is from about 15° to about 160° C, and amore preferred range is from about 30° to about 130° C.

The time of the polymerization may be varied within wide limitsdepending upon factors such as the radical initiator selected, theamount of radical initiator employed, the organic medium chosen, themonomers selected, the ratio of monomers to organic medium and otherfactors. Generally, the polymerization time is in the range of fromabout 30 minutes to about 50 hours. A preferred time is in the range offrom about 1 to about 30 hours, and a more preferred time is in therange of from about 2 to about 20 hours. A conventional method ofraising the polymerization temperature in the course of polymerizationis preferred in the present invention as the method of shortening thepolymerization time.

The polymerization reaction can be carried out either at atmosphericpressure, under a pressure above atmospheric or under a reducedpressure.

The porous polymers according to this invention may be prepared bypolymerizing the monomer mixture in the presence of the organic liquidby a conventional solution polymerization method or suspensionpolymerization method, for examples, described in "Preparative Methodsof Polymer Chemistry" by W. R. Sorenson and T. W. Campbell, published byJohn & Wiley and Sons, Inc., New York (1961).

In carrying out a suspension polymerization in water an important factoris the solubility of the organic medium in water. That is, when thesolubility of the organic medium employed in water, is high, itsometimes happens that the concentration of the organic medium in theoil phase differs from the initial concentration. At such an occasionthe solubility of the organic medium in water can be decreased by addingto the water a salt such as sodium chloride, calcium chloride, etc., inan amount of, typically, from about 0.1 to about 20 percent, preferablyfrom about 0.5 to about 15 percent, and most preferably from about 1 toabout 10 percent, by weight based on the weight of the water.

It is preferred to employ a suspending agent in carrying out thesuspension polymerization.

Exemplary suspending agents which may be employed in the suspensionpolymerization in water include, for example, viscous substances such asgum arabic, alginic acid, tragacanth, agar-agar, methyl cellulose,hydroxyethyl cellulose, carboxymethyl cellulose, starch, gelatin, glue;synthetic high molecular weight polymers such as sodium polyacrylate,polyvinyl alcohol, polyvinylpyrrolidone; inorganic substances such askaolin, bentonite, a hydrated complex of magnesium silicate, titaniumdioxide, zinc oxide, calcium carbonate, talcum, barium sulfate,hydroxyapatite, aluminum hydroxide, calcium oxalate.

If necessary or desired, it is effective to additionally employ pHadjusting agents such as sodium phosphate, sodium dihydrogen phosphate,ammonium sulfate, sodium acetate, sodium hydrogen carbonate and anionsurfactants, including soaps of fatty acids, sodium dodecyl benzenesulfonate, sodium dodecyl sulfate, sodium lauryl sulfate, etc., in thesuspension polymerization in water. The suspending agent, the pHadjusting agent and the anion surfactant can each be employed,respectively, in an amount of from about 0.001 to about 10 percent,preferably from about 0.01 to about 5 percent, more preferably fromabout 0.02 to about 3 percent, by weight based on the weight of thewater employed.

The weight ratio of water to the mixture of monomers and organic mediumwhich may be employed in the suspension polymerization in water is inthe range of from about 0.5 to about 15, preferably from about 1 toabout 10, and more preferably from about 2 to about 8.

The polymers which are obtained under the above described polymerizationconditions still contains unreacted monomer and organic medium. Suchunreacted monomer and organic medium can effectively be removed by: (1)a method comprising immersing the polymers in a water soluble mediumwhich dissolves the monomer and organic medium for at least 2 to 5hours, subsequently filtering the polymers and washing the polymers withwater: or (2) a method comprising placing the polymers in a column andpassing a water soluble medium which dissolves the monomer and organicmedium and subsequently water through the column.

Exemplary washing media include methanol, ethanol, acetone, dioxane.acetonitrile, dimethyl formamide and the like which are soluble inwater. Such washing media remaining in the polymers can readily andeasily be eliminated by washing with water.

Generally, the efficiency of ion exchange resins is determined byequilibrium factor and kinetic factor. The former, that is, selectivity,is basically determined by the chemical structure of the resins, and thelatter, that is, the ion exchange rate, greatly depends upon thephysical structure of the resin. This ion exchange rate governs theefficiency of ion exchange resins.

It has now been found that the ion exchange resins obtained in thepresent invention possess a remarkably high ion exchange rate.

In the present invention, the apparent ion exchange rate of anionexchange resins is measured by the following method.

Anion exchange resins are packed in a column. Firstly, a sufficientamount of a 1N hydrochloric acid solution is passed through the columnand secondly a sufficient amount of ethanol is passed through the columnto remove hydrochloric acid from voids in the resins and from betweenthe resins. Then, the resins thus treated are introduced to a largeamount of a 1N aqueous sulfuric acid solution, and, while stirring, theconcentration of chloride ion in the solution is measured with thepassage of time by a chloride ion electrode. Sulfate ion is nearlyquantitatively exchanged since sulfate ion is present in great excess.The time required for exchanging one half of the total chloride ionsadsorbed in the resins for sulfate ions " t1/2 " is used as theindicator of the ion exchange rate.

It is well known that the ion exchange rate is remarkably increased bymaking resins porous.

The porous anion exchange resins according to this invention have agreatly increased ion exchange rate due to their increased pore volumeand decreased density of very minute particles.

It has already been pointed out that in the production of porous resinsusing organic liquid as a phase separator, the amount of organic liquidnecessary for the phase separation becomes smaller when the amount ofcross-linkable monomers becomes greater. With regard tostyrene-divinylbenzene series polymers, this is described in Journal ofChemical Society, p. 304 (1965). Further, it is described in JapanesePatent Laid Open 71790/1973 that in the production of porous resins bycopolymerizing a vinyl nitrogen heterocyclic monomer with a polyvinylaromatic hydrocarbon the amount of a precipitant should be decreasedwhen the rate of cross-linking is increased.

It has now been found that there is often proportional relationshipbetween the amount of cross-linkable polymerizable monomers and therelative amount of organic liquid necessary for effecting phaseseparation, and that the ion exchange rate decreases with increaseddegrees of cross-linking and increases with increased relative amountsof the phase separator.

These two facts become very important in the preparation of porous ionexchange resins according to this invention, as will be explained byreferring to the following Examples 1 to 7.

Methyl benzoate acts as a solvent for polydivinylbenzene andpolyethylvinylbenzene and as a precipitant for poly-4-vinylpyridine atthe same time. In Example 5, the solubility of the copolymer in methylbenzoate is increased due to the smaller amount of 4-vinylpyridine ascompared to Example 1, and, as a result, the porosity of the copolymerof Example 5 is lowered. In order to increase the degree ofcross-linking while maintaining the same porosity as in Example 1, it isnecessary to increase the amount of methyl benzoate as in Example 2.

On the other hand, when an organic medium which precipitates a polymerof a monomer having a plurality of CH₂ ═C< groups and dissolves apolymer of a copolymerizable monoethylenically unsaturated monomer orconjugated diene monomer at the same time is employed as a phaseseparator, it is necessary to decrease the amount of organic medium withan increase in the rate of cross-linking.

With regard to the relationship between the ion exchange rate and thestructure of the ion exchange resins, when only the degree of crosslinking is increased while maintaining the amount of organic mediumconstant, the ion exchange rate diminishes due to increasedcross-linking density. This is clearly seen by comparing Example 1 withExample 5. In this instance, when the ratio of organic medium as a phaseseparator is increased as in Example 2, an increase ion exchange rate isobserved once again. Also, as in Example 7 when a precipitant isemployed, pore volume decreases and, accordingly, the ion exchange ratelowers.

Thus, the present invention provides a method of preparing ion exchangeresins of high efficiency. According to this invention, anion exchangeresins having a similar structure and rate of ion exchange with regardto different degrees of cross-linking can be prepared by appropriatelyselecting a monomer mixture and an organic medium, and varying theamount of the organic medium selected.

In this invention, the pore size distribution and pore volume aremeasured by the mercury penetration method described in "Fine ParticleMeasurement" by Clyde Orr, Jr. and J. M. Dallavalle, published byMacmillan Co., New York (1959). The apparatus employed is a MercuryPenetration Porosimeter, 900/910 Series, made by Micrometrics InstrumentCorporation, and calculations are made from the following equation;

        r = 176.8/p                                                           

wherein r represents pore diameter in A; and p represents the pressureof the mercury in p.s.i. when mercury is gradually forced into 0.1 to0.5 g of thoroughly dried porous polymer until the pressure reaches50,000 p.s.i.

According to this method, it is possible to measure pore diameters assmall as about 40 A. In the invention, a pore diameter is defined to beabout 40 A or more.

The polar, porous polymers according to this invention have a porediameter of from about 40 to about 10,000 A, and preferably from about60 to about 5,000 A.

The porous polymers according to this invention has a wide range of useas anion exchange resins, stationary phases for gas chromatography andliquid chromatography, adsorbents for acidic gases such as hydrogensulfide, sulfurous acid gas, nitrogen oxides, mercaptans, fatty acids,basic gases such as ammonia, amines and other offensive odors,adsorbents for heavy metal ions in water, surfactants, coloringmaterials, high molecular weight polymers, carriers for immobilizedenzymes and for affinity chromatography, etc.

This invention will now be illustrated in more detail by severalnon-limiting examples.

EXAMPLES 1-7

Into a 3 liter four necked flask equipped with a four paddle stainlesssteel stirrer thermometer, reflux condenser and nitrogen inlet wereadded freshly distilled 4-vinylpyridine, technical divinylbenzenecontaining 56% by weight of divinylbenzene and 44% by weight ofethylvinylbenzene in an amount as set forth in Table 1, an organicmedium as set forth in Table 1, 0.5 g of benzoyl peroxide as the radicalinitiator and water containing 0.5% by weight of hydroxyethyl cellulose(molecular weight: 4 × 10⁴) and 5% by weight of sodium chloride in anamount set forth in Table 1, and the contents of the flask were agitatedat 250 rpm to form a uniform dispersion. Then the suspension was heatedwith agitation at 250 rpm firstly at 60° C for 4 hours, secondly at 75°C for 4 hours and thirdly at 90° C for 4 hours. The resulting polymerwas subjected to wet classification with a set of sieves andsubsequently thoroughly washed with methanol to remove unreactedmonomers and organic medium. The porous polymer thus obtained was in theform of spherical particles. The properties of the porous polymer areshown in Table 1.

EXAMPLES 8

Into the same flask as in Example 1 were charged 50 g of freshlydistilled acrylonitrile, 33 g of styrene, 17 g of technicaldivinylbenzene containing 80% by weight of divinylbenzene and 20% byweight of ethylvinylbenzene, 150 g of toluene, 50 g of cyclohexanol and2 g of benzoyl peroxide. To the flask were added 2000 g of watercontaining 9 g of sodium dodecylsulfate, 5 g of sodium dihydrogensulfate, 20 g of sodium chloride and 10 g of hydroxyapatite (averageparticle diameter: 0.3 micron, and the contents of the flask wereagitated at 300 rpm to form a uniform dispersion. Then the suspensionwas heated firstly at 50° C for 4 hours, secondly at 60° C for 4 hoursand thirdly at 70° C for 4 hours with agitation at 300 rpm. The reactionmixture was treated in the same manner as in Example 1 to give a porouspolymer in the form of spherical particles having a particle diameter of30 to 220 microns. The yield of the polymer was 96%. The structuralproperties of the porous polymer were as follows;

Bulk density : 0.31 g/cm³

Average pore diameter : 4820 A

Pore volume : 1.67 cm³ /g

EXAMPLE 9

Into the same flask as in Example 1 were charged 50 g of freshlydistilled methacrylonitrile, 50 g of technical divinylbenzene containing80% by weight of divinylbenzene and 20% by weight of ethylvinylbenzene,1 g of 2,2'-azobis (2,4-dimethylvaleronitrile) and 400 g of n-butylacetate, and the contents mixed. Then, to the flask were added 1200 g ofwater containing 12 g of methylcellulose and 2.4 g of sodium chloride,and the contents of the flask were agitated at 300 rpm to form a uniformdispersion. The suspension was then heated at 60° C for 30 hours withagitation at 300 rpm. The yield of the polymer was 98%. The resultingpolymer was subjected to wet classification with a set of sieves andthoroughly washed with methanol. The porous polymer thus obtained was inthe form of spherical particles having a diameter of 40 to 320 microns.The polymer had an average pore diameter of 150 A.

EXAMPLE 10-12

Into the same flask as in Example 1 were charged 60 g of2-methyl-5-vinylpyridine, 35 g of styrene, 5 g of trivinylbenzene, 1 gof azobisisobutyronitrile and 200 g of a mixed organic medium of methylisobutyl ketone and isooctane in a ratio as set forth in Table 2, andthe system mixed. Then, to the flask were added 2000 g of watercontaining 80 g of sodium chloride and 2 g of polyvinyl alcohol(molecular weight: 5 × 10⁵) and the contents of the flask agitated at400 rpm to form a uniform dispersion. The suspension was then heated at80° C for 8 hours. The resulting polymer was subjected to wetclassification with a set of sieves and thoroughly washed with methanol.The porous polymer thus obtained was in the form of spherical particles.The properties of the polymer are shown in Table 2.

EXAMPLE 13

20 g of acrylamide recrystallized from ethyl acetate, 5 g ofN,N'-methylenediacrylamide and 0.5 g of2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile were dissolved in 50 gof ethylbenzene, and the resulting solution charged into a 200 mlpressure-resistant glass ampoule. The ampoule was then sealed and heatedin an oil bath at 140° C for 40 minutes. After cooling, the contents ofthe ampoule were taken out, pulverized, washed with acetone in order toremove unreacted monomers and ethylbenzene and subjected to wetclassification with a set of sieves to give a polymer having the desiredparticle size.

The dried porous polymer had an average diameter of 520 A, a pore volumeof 0.62 cm³ /g and a bulk density of 0.32.

EXAMPLE 14

40 g of N-vinylcarbazole, 20 g of methyl methacrylate, 20 g ofdivinylpyridine and 1.5 g of azobisisobutyronitrile were dissolved into300 g of methylisobutyl ketone and the resulting solution charged into a2 liter four necked flask equipped with a four paddle stainless steelstirrer, thermometer, reflux condenser and nitrogen inlet. To the flaskwere added 400 g of water containing 1 g of gelatin, 1 g of sodiumchloride and 1 g of bentonite, and the contents of the flask vigorouslyagitated until a uniform dispersion was obtained. The suspension wasthen heated firstly at 50° C for 2 hours, secondly at 70° C for 4 hoursand thirdly at 90° C for 4 hours with agitation. The yield of thepolymer was 94%. The polymer thus obtained was placed in a filteringvessel equipped with a glass filer and thoroughly washed with water andsubsequently with acetone and further with water to remove unreactedmonomers and organic medium. The porous polymer had an average pore sizeof 150 A and a pore volume of 1.05 cm³ /g.

EXAMPLES 15-17

2 g of styrene, 8 g of N-vinylpyrrolidone, 10 g of ethyleneglycoldimethacrylate and 0.2 g of 2-cyano-2-propylazoformamide were dissolvedin 60 g of a mixed organic liquid of ethyl acetate and diethyl phthalatein a ratio as set forth in Table 3, and the resulting solution wascharged into a 100 ml pressure-resistant glass ampoule. The ampoule wasthen sealed and heated at 120° C for 1.5 hours. The reaction mixture wastreated in the same manner as in Example 13 to yield porous polymers.The physical properties of the polymers are shown in Table 3.

EXAMPLES 18-21

The procedures of Example 1 for preparing porous polymers were repeatedexcept that the polymerization conditions as set forth in Table 4 wereemployed. The properties of the resulting porous polymers are shown inTable 4.

EXAMPLES 22-24

The procedures of Example 8 for preparing porous polymers were repeatedexcept that 0.5 g of benzoyl peroxide was employed instead of 2 g ofbenzoyl peroxide and the conditions as set forth in Table 4 wereemployed. The properties of the resulting porous polymers are shown inTable 4.

EXAMPLE 25

The procedure of Example 14 for preparing a porous polymer was repeatedexcept that the polymerization conditions as set forth in Table 5 wereemployed. The properties of the resulting porous polymer are shown inTable 5.

EXAMPLES 26-28

The monomer mixtures as set forth in Table 5 and 1 g ofazobisisobutyronitrile were dissolved into the organic liquid set forthin Table 5, and to the resulting solution were added 1600 g of watercontaining 6.4 g of carboxymethyl cellulose (molecular weight: 1.2 ×10⁴) and 3 g of sodium chloride and the mixture was vigorously agitateduntil a uniform dispersion was obtained. The suspension was then heatedat 70° C for 24 hours, whereafter the reaction mixture was treated inthe same manner as in Example 1. The properties of the resulting porouspolymer are shown in Table 5.

EXAMPLE 29

The procedure of Example 1 for preparing a porous polymer was repeatedexcept that an autoclave equipped with a stirrer and thermometer wasemployed instead of the flask, and the temperature was set at 70° C, thetime of the polymerization was 15 hours and the polymerizationconditions as set for in Table 5 were employed. The properties of theresulting porous polymer are shown in Table 5.

EXAMPLES 30-33

The procedures of Example 1 for preparing porous polymers were repeatedexcept that the polymerization conditions as set forth in Table 6 wereemployed. The properties of the resulting porous polymers are shown inTable 6.

                                      Table 1                                     __________________________________________________________________________    Polymerization                                                                                         Suspending                                                                    Agent                                                Monomers         Organic Hydorxyethyl                                         Example                                                                            4VP*                                                                              EVB*                                                                              DVB*                                                                              Medium  cellulose                                                                            NaCl                                                                              Water                                                                             Yield                                 No.  (g) (g) (g) (g)     g(%)   g(%)                                                                              (g) (%)                                   __________________________________________________________________________    1    82.2                                                                               7.8                                                                              10  MBz**                                                                             130 4 (0.5)                                                                              40 (5)                                                                            800 98                                    2    46.4                                                                              23.6                                                                              30  MBz 230 6 (0.5)                                                                              60 (5)                                                                            1200                                                                              98                                    3    82.2                                                                               7.6                                                                              10  MBz 50  2.5 (0.5)                                                                            25 (5)                                                                            500 97                                    4    46.4                                                                              23.6                                                                              30  MBz 70  3 (0.5)                                                                              30 (5)                                                                            600 99                                    5    "   "   "   MBz 130 4 (0.5)                                                                              40 (5)                                                                            800 98                                    6    "   "   "   Ebz**                                                                             130 4 (0.5)                                                                              40 (5)                                                                            800 99                                    7    82.2                                                                               7.8                                                                              10  ISO**                                                                             30  2.5 (0.5)                                                                            25 (5)                                                                            500 98                                    __________________________________________________________________________    Porous Polymer                                                                                  Exchange                                                                             Cl.sup.- /SO.sub.4.sup.--                                                             Porosity                                                       Capacity                                                                             Exchange                                                                              Average                                                  Particle                                                                            (HCl   Rate    Pore  Pore                                   Example                                                                             Bulk  Diameter                                                                            Type)  t1/2    Diameter                                                                            Volume                                 No.   Density                                                                             (micron)                                                                            (meq/g)                                                                              (second)                                                                              A     (cm.sup.3 /g                           __________________________________________________________________________    1     0.29  40-200                                                                              5.92   1.54    580   0.88                                   2     0.20  40-280                                                                              3.70   1.48    620   1.52                                   3     0.38  30-250                                                                              5.76   10.8    <40   --                                     4     0.34  40-220                                                                              3.75   10.2    <40   --                                     5     0.28  30-190                                                                              3.69   4.42    135   0.98                                   6     0.27  30-300                                                                              3.72   4.02    710   1.12                                   7     0.44  30-290                                                                              5.98   13.4    505   0.23                                   __________________________________________________________________________     *4VP : 4-Vinylpyridine, EVB : Ethylvinylbenzene                               DVB : Divinylbenzene                                                          **MBz : Methyl benzoate, EBz : Ethyl benzoate, ISO : Isooctane           

                  Table 2                                                         ______________________________________                                                    Porous Polymer                                                                        Porosity                                                                                  Average                                                         Bulk   Particle                                                                             Pore   Pore                                   Ex.  Organic Medium                                                                             Den-   Diameter                                                                             Diameter                                                                             Volume                                 No.  (g.)         sity   (micron)                                                                             (A)    (cm.sup.3 /g)                          ______________________________________                                        10   MIBK*    180                                                                                   0.14 50 - 180                                                                             130    1.08                                      Isooctane                                                                              20                                                              11   MIBK     170                                                                                   0.16 40 - 200                                                                             560    1.29                                      Isooctane                                                                              30                                                              12   MIBK     160                                                                                   0.15 60 - 220                                                                             1300   1.56                                      Isooctane                                                                              40                                                              ______________________________________                                         *MIBK:Methyl isobutyl ketone                                             

                  Table 3                                                         ______________________________________                                                         Porous Polymer                                                                   Porosity                                                                                Average                                                                Bulk   Pore   Pore                                     Ex.  Organic Medium    Den-   Diameter                                                                             Volume                                   No.  (g)               sity   (A)    (cm.sup.3 /g)                            ______________________________________                                        15   Ethyl acetate                                                                              40                                                                                     0.18 520    0.21                                        Diethyl phthalate                                                                          20                                                          16   Ethyl acetate                                                                              30                                                                                     0.17 930    0.23                                        Diethyl phthalate                                                                          30                                                          17   Ethyl acetate                                                                              20                                                                                     0.17 2160   0.24                                        Diethyl phthalate                                                                          40                                                          ______________________________________                                    

                                      Table 4                                     __________________________________________________________________________                                     Porous Polymer                                                                         Exchange                                                                           Cl.sup.- /SO.sub.4.sup.-                                                 Capacity                                                                           Exchange                                                                            Average                                                                             Pore                            Polymerization      Bulk                                                                             Particle                                                                            (HCl Rate  Pore  Vol-               Ex.                                                                              Monomer Mixture                                                                           Organic Medium                                                                              Water                                                                             Den-                                                                             Diameter                                  Type)                                          t1/2  Diameter                                                                           ume                 No.                                                                              (g)         (g)           (g) sity                                                                             (micron)                                                                           (meq/g)                                                                             (second)                                                                            (A)  (cm.sup.3           __________________________________________________________________________                                                              /g)                 18 4-Vinylpyridine                                                                         40                                                                              Dimethyl phthalate                                                2-Vinylpyridine                                                                         30          150 1200                                                                              0.26                                                                             60-220                                                                             5.21  1.98   320 0.88                   Ethylvinylbenzene                                                                        5                                                                              Acetophenone                                                                            50                                                   Divinylbenzene                                                                   25                                                                         19   "         Diethyl phthalate                                                                       150 "   0.24                                                                             40-190                                                                             5.18  1.87   980 1.26                               Acetophenone                                                                            50                                                   20   "         Di-n-butyl phthalate                                                                    150 "   0.21                                                                             50-250                                                                             5.29  1.69  1520 1.54                               Acetophenone                                                                            50                                                   21 2-Vinylpyridine                                                                         60                                                                              sec-Butanol                                                                             150 2200                                                                              0.18                                                                             40-280                                                                             4.70  1.13  2500 1.88                   Ethylene glycol                                                               dimethacrylate                                                                          40                                                                              Cyclohexanol                                                                            150                                                  22 2-Methyl-5-Vinyl-                                                                         Benzene   180  700                                                                              0.28                                                                             60-250                                                                             4.02  2.92   850 0.93                   pyridine  40                                                                  Acrylonitrile                                                                           40                                                                  2,5-Divinylpyridine                                                                     20                                                               23   "         Toluene   180 "   0.26                                                                             80-300                                                                             4.10  2.73  1290 1.22                24   "         m-Xylene  180 "   0.25                                                                             80-250                                                                             4.11  2.55  2830 1.44                __________________________________________________________________________

                                      Table 5                                     __________________________________________________________________________                                        Porous Polymer                                                                          Porosity                                                                      Average                         Polymerization                           Particle                                                                           Pore Pore                       Example                                                                            Monomer Mixture                                                                            Organic Medium                                                                              Water                                                                             Bulk Diameter                                                                           Diameter                                                                           Volume                     No.  (g)          (g)           (g) Density                                                                            (micron)                                                                           (A)  (cm.sup.3 /g               __________________________________________________________________________    25   2-Vinylpyridine                                                                         50 n-Octanol 150 1600                                                                              0.18 30-200                                                                             150  0.72                            Pentaerythritol                                                               tetramethacrylate                                                                          anisole   150                                                              50                                                             26   1-Vinyl-2-methyl-                                                                          Cyclohexanol                                                                            20  1600                                                                              1.19 50-250                                                                             170  0.92                            imidazole 60                                                                               m-Xylene  100                                                    Ethylene glycol                                                               dimethacrylate                                                                          40                                                             27     "          Cyclohexanol                                                                            150 "   0.17 40-320                                                                             560  1.84                                         m-Xylene  150                                               28     "          Cyclohexanol                                                                            100 "   0.15 40-300                                                                             1300 2.52                                         m-Xylene  200                                               29   Acrylonitrile                                                                           40 Methylene chloride                                               1,3-Butadiene                                                                           35           100 1400                                                                               0.2 20-220                                                                             1260 1.86                            Divinylbenzene                                                                          20 Methyl ethyl ketone                                              Ethylvinylbenzene                                                                       5            150                                               __________________________________________________________________________

                                      Table 6                                     __________________________________________________________________________                                         Porous Polymer                                                                          Porosity                                                                      Average                        Polymerization                            Particle                                                                           Pore Pore                      Example                                                                            Monomer Mixture                                                                             Organic Medium                                                                              Water                                                                             Bulk Diameter                                                                           Diameter                                                                           Volume                    No.  (g)           (g)           (g) Density                                                                            (micron)                                                                           (A)  (cm.sup.3 /g)             __________________________________________________________________________    30   2-Vinylimidazole                                                                         50 Nitroethane                                                                             200 2000                                                                              0.16 40-200                                                                             820  1.96                           Ethylene glycol                                                                             Heptane   100                                                   dimethacrylate                                                                           50                                                            31     "           Chlorobenzene                                                                           200 1800                                                                              0.20 50-320                                                                             4200 2.20                                         Octane    50                                               32   2-Methyl-5-vinyl-                                                                           O-Dichlorobenzene                                                                       100 1800                                                                              0.22 60-400                                                                             3200 1.88                           pyridine   25                                                                 N-Vinylcarbazole                                                                         50 n-Octanol 50                                                    Divinylbenzene                                                                           20                                                                 Ethylvinylbenzene                                                                        5                                                             33   Methyl methacrylate                                                                      40 Cyclohexanol                                                                            150 1500                                                                              0.30 50-250                                                                              75  0.21                           2-Vinylpyridine                                                                          50                                                                 Divinylpyridine                                                                          10                                                            __________________________________________________________________________

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A method of producing a polar, porous polymercomprising polymerizing a monomer mixture comprising:(A) about 2 toabout 98 percent of at least one cross-linkable monomer having aplurality of CH₂ ═C< groups and (B) about 98 to about 2 percent byweight of at least one monomer selected from the group consisting of (i)copolymerizable monoethylenically unsaturated monomers and (ii)conjugated diene monomers, about 15 to about 100 percent by weight ofthe total monomers (A) and (B) being polar monomers,in the presence ofan organic medium which does not react with any of monomers (A) and (B),and selected from the group consisting of: (I) a mixed organic liquidconsisting essentially of at least one liquid selected from Group (i)and at least one liquid selected from Group (iii); Ii. a mixed organicliquid consisting of at least one liquid selected from Group (i) and atleast one liquid selected from Group (iii); Iii. a mixed organic liquidconsisting of at least one liquid selected from Group (ii) and at leastone liquid selected from Group (iii); and Iv. one liquid selected fromGroup (iii);wherein Group (i) liquids dissolve all of the homopolymersof the monomers chosen; Group (ii) liquids do not dissolve any of thehomopolymers chosen, and Group (iii) liquids dissolve at least onehomopolymer of the monomers chosen but do not dissolve at least anotherhomopolymer of the monomers chosen.
 2. The method of claim 1, whereinthe polymerization is carried out in the presence of a radicalinitiator.
 3. The method of claim 1, wherein the polymerization iscarried out with said monomer mixture and organic medium in suspensionin an aqueous medium.
 4. The method of claim 1, wherein the amount ofpolar monomers is in the range of from about 20 to about 90 percent byweight based on the total weight of monomers (A) and (B).
 5. The methodof claim 1, wherein said organic medium is employed in an amount D inpercent by weight based on the total weight of monomers (A) and (B) andrepresented by the equation

        about 7√X < D < about 500√X                             

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 6. The method of claim 1, whereincross-linkable monomer (A) is employed in an amount of from about 3 toabout 80 percent by weight based on the total weight of monomers (A) and(B).
 7. The method of claim 6, wherein the amount of cross-linkablemonomer (A) is in the range of from about 4 to about 60 percent byweight based on the total weight of monomers (A) and (B).
 8. The methodof claim 1, wherein cross-linkable monomer (A) is selected from thegroup consisting of divinylbenzenes, trivinylbenzenes, divinylpyridines,N,N'-methylene diacrylamide, ethylene glycol dimethacrylate andpentaerythritol tetramethacrylate.
 9. The method of claim 1, whereincopolymerizable monoethylenically unsaturated monomer (B) (i) is a vinylnitrogen heterocyclic compound.
 10. The method of claim 9 wherein saidvinyl nitrogen heterocyclic compound is selected from the groupconsisting of 2-vinylpyridine, 4-vinylpyridine,2-methyl-5-vinylpyridine, 1-vinyl-2-methylimidazole, N-vinylpyrrolidoneand N-vinylcarbazole.
 11. The method of claim 1, wherein copolymerizablemonoethylenically unsaturated monomer (B) (i) is selected from the groupconsisting of styrene, ethylvinylbenzenes, acrylonitrile,methacrylonitrile, acrylamide and methyl methacrylate.
 12. The method ofclaim 1, wherein conjugated diene compound (B) (ii) is 1,3-butadiene.13. A method of producing a polar, porous polymer comprisingpolymerizing a monomer mixture comprising:(A) about 2 to about 98percent by weight of at least one cross-linkable monomer having aplurality of CH₂ ═C< groups and (B) about 98 to about 2 percent byweight of at least one monomer selected from the group consisting of (i)copolymerizable monoethylenically unsaturated monomers and (ii)conjugated diene monomers, about 15 to about 100 percent by weight ofthe total monomers (A) and (B) being polar monomers,in the presence ofan organic medium consisting essentially of about 2 to about 98 percentby weight of at least one liquid which dissolves all of the homopolymersof monomers (A) and (B) and about 98 to 2 percent by weight of at leastone liquid which dissolves at least one homopolymer of monomers (A) and(B) but does not dissolve at least another homopolymer of monomers (A)and (B), said organic medium being employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 7√X < D < about 500√X                             

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 14. The method of claim 13,wherein said organic medium is employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 20√X < D < about 200√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 15. The method of claim 14,wherein said organic medium is employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 34√X < D < about 150√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 16. The method of claim 13,wherein said monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, divinylpyridines, (b) at least onemonomer selected from the group consisting of 2-vinylimidazole,N-vinyl-2-methylimidazole and 4-vinylpyridine, and (c) at least onemonomer selected from the group consisting of styrene,ethylvinylbenzenes, 2-vinylpyridine, 2-methyl-5-vinylpyridine, methylmethacrylate, methyl acrylate and 1,3-butadiene, and said organic mediumconsists essentially of: (a) at least one liquid selected from the groupconsisting of acetophenone, cyclohexane, tetrachloroethane, benzylalcohol, benzonitrile, nitroethane and nitropropane and (b) at least oneliquid selected from the group consisting of benzene, toluene, xylenes,ethylbenzene, diethylbenzenes and tetraline, butanols, pentanols,hexanols, cyclohexanol, octanols, ethyl acetate, butyl acetates, ethylpropionate, butyl propionates and butyl adipates, methyl benzoate, ethylbenzoate, dimethyl phthalate, diethyl phthalate, methyl ethyl ketone,methyl isobutyl ketone, diisobutyl ketone, chlorobenzene ando-dichlorobenzene.
 17. The method of claim 13, wherein said monomermixture consists essentially of: (a) at least one monomer selected fromthe group consisting of ethylene glycol dimethacrylate, divinylbenzenes,trivinylbenzenes and divinylpyridines, (b) at least one monomer selectedfrom the group consisting of 2-vinylpyridine and2-methyl-5-vinylpyridine and (c) at least one monomer selected from thegroup consisting of styrene, ethylvinylbenzenes, methyl methacrylate,methyl acrylate and 1,3-butadiene, and said organic medium consistsessentially of: (a) at least one liquid selected from the groupconsisting of benzene, toluene, xylenes, cyclohexanone, methyl ethylketone, anisole, methyl benzoate, ethyl propionate, dimethyl phthalate,chlorobenzene and o-dichlorobenzene and (b) at least one liquid selectedfrom the group consisting of butanols, pentanols, hexanols, cyclohexanoland octanols.
 18. A method of producing a polar, porous polymercomprising polymerizing a monomer mixture comprising:(A) about 2 toabout 98 percent by weight of at least one cross-linkable monomer havinga plurality of CH₂ ═C< groups and (B) about 98 to about 2 percent byweight of at least one monomer selected from the group consisting of (i)copolymerizable monoethylenically unsaturated monomers and (ii)conjugated diene monomers, about 15 to about 100 percent by weight ofthe total monomers (A) and (B) being polar monomers,in the presence ofan organic medium consisting essentially of about 2 to about 98 percentby weight of at least one liquid which does not dissolve any of thehomopolymers of monomers (A) and (B) and about 98 to about 2 percent byweight of at least one liquid which dissolves at least one homopolymerof monomers (A) and (B) but does not dissolve at least anotherhomopolymer of monomers (A) and (B) and represented by the equation

        about 7√X < D about 500√X                               

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 19. The method of claim 18,wherein said organic medium is employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 20√X < D < about 200√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 20. The method of claim 19,wherein said organic medium is employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 34√X < D < about 150√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 21. The method of claim 18,wherein said monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, trivinylbenzenes, trivinylbenzenes anddivinylpyridines, (b) at least one monomer selected from the groupconsisting of 2-vinylimidazole, N-vinyl-2-methylimidazole and4-vinylpyridine and (c) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes, 2-vinylpyridine,2-methyl-5-vinylpyridine, methyl methacrylate, methyl acrylate and1,3-butadiene, and said organic medium consists essentially of: (a) atleast one liquid selected from the group consisting of hexanes,cyclohexane, heptanes, octanes and decanes and (b) at least one liquidselected from the group consisting of benzene, toluene, xylenes,ethylbenzene, diethylbenzenes, tetraline, butanols, pentanols,cyclohexanol, octanols, ethyl acetate, butyl acetates, ethyl propionate,butyl propionates, butyl adipates, methyl benzoate, ethyl benzoate,dimethyl phthalates, diethyl phtalates, methyl ethyl ketone, methylisobutyl ketone, diisobutyl ketone, chlorobenzene, ando-dichlorobenzene.
 22. The method of claim 18, wherein said monomermixture consists essentially of: (a) at least one monomer selected fromthe group consisting of ethylene glycol dimethacrylate, divinylbenzenesand divinylpyridines, (b) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes, methyl methacrylate,2-vinylpyridine, 2-methyl-5-vinylpyridine and 1,3-butadiene, and (c)acrylonitrile, and said organic medium consists essentially of: (a) atleast one liquid selected from the group consisting of hexanes,heptanes, octanes, decanes, cyclohexanes, pentanols, hexanols, octanolsand cyclohexanol, and (b) at least one liquid selected from the groupconsists of benzene, toluene, xylenes, ethylbenzene, ethyl acetate,methyl propionate, butyl propionates, butyl adipates, methyl benzoate,ethyl benzoate, diethyl phthalate, propionitrile, butyronitriles,nitroethane, nitropropane, methyl ethyl keton, methyl isobutyl ketoneand cyclohexanone.
 23. A method of producing a polar, porous polymercomprising polymerizing a monomer mixture comprising:(A) about 2 toabout 98 percent by weight of at least one cross-linkable monomer havinga plurality of CH₂ 'C< groups and (B) about 2 to about 98 percent byweight of at least one monomer selected from the group consisting of (i)copolymerizable monoethylenically unsaturated monomers and (ii)conjugated diene monomers, about 15 to about 100 percent by weight ofthe total monomers (A) and (B) being polar monomers,in the presence ofat least two organic liquids, each of which dissolves at least onehomopolymer of monomers (A) and (B) but does not dissolve at leastanother homopolymer of monomers (A) and (B) in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 20√X < D < about 200 √X                           

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 24. The method of claim 23,wherein said organic liquids are employed in an amount D in percent byweight based on the total weight of monomers (A) and (B) and representedby the equation

        about 34√X < D < about 150√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 25. The method of claim 23,wherein said monomer mixture consists essentially of: (a) at least onemonomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, trivinylbenzenes and divinylpyridines,(b) at least one monomer selected from the group consisting of2-vinylimidazole, N-vinyl-2-methylimidazole and 4-vinylpyridine and (c)at least one monomer selected from the group consisting of styrene,ethylvinylbenzenes, 2-vinylpyridine, 2-methyl-5-vinylpyridine, methylmethacrylate, methyl acrylate and 1,3-butadiene and said organic mediumconsists essentially of at least two liquids selected from the groupconsisting of benzene, toluene, xylenes, ethylbenzene, diethylbenzenes,tetraline, butanols, pentanols, cyclohexanol, octanols, ethyl acetate,butyl acetates, ethyl propionate, butyl propionates, butyl adipates,methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate,methyl ethyl ketone, diisobutyl ketone, chlorobenzene, ando-dichlorobenzene.
 26. The method of claim 23, wherein said monomermixture consists essentially of: (a) at least one monomer selected fromthe group consisting of ethylene glycol dimethacrylate divinylbenzenes,trivinylbenzenes and divinylpyridines, (b) at least one monomer selectedfrom the group consisting of 2-vinylpyridine and2-methyl-5-vinylpyridine, and (c) at least one monomer selected from thegroup consisting of styrene, ethylvinylbenzenes, methyl methacrylate,methyl acrylate and 1,3-butadiene and said organic medium consistsessentially of at least two liquids selected from the group consistingof butanols, pentanols, octanols and cyclohexanol.
 27. The method ofclaim 23, wherein said monomer mixture consists essentially of: (a) atleast one monomer selected from the group consisting of ethylene glycoldimethacrylate, divinylbenzenes, trivinylbenzenes, and divinylpyridines,(b) at least one monomer selected from the group consisting of styrene,ethylvinylbenzenes, methyl methacrylate, 2-vinylpyridine,2-methyl-5-vinylpyridine and 1,3-butadiene and (c) acrylonitrile andsaid organic medium consists essentially of at least two liquidsselected from the group consisting of benzene, toluene, xylenes,ethylbenzene, ethyl acetate, methyl propionate, butyl propionates, butyladipates, methyl benzoate, ethyl benzoate, diethyl phthalate,propionitrile, butyronitrile, nitroethane, nitropropane, methyl ethylketone, methyl isobutyl ketone and cyclohexanone.
 28. A method ofproducing a polar, porous polymer comprising polymerizing a monomermixture comprising:(A) about 2 to about 98 percent by weight of at leastone cross-linkable monomer having a plurality of CH₂ ═< groups and (B)about 98 to about 2 percent by weight of at least one monomer selectedfrom the group consisting of (i) copolymerizable monoethylenicallyunsaturated monomers and (ii) conjugated diene monomers, about 15 toabout 100 percent by weight of the total monomers (A) and (B) beingpolar monomers,in the presence of one organic liquid which dissolves atleast one homopolymer of monomers (A) and (B) but does not dissolve atleast another homopolymer of monomers (A) and (B) in an amount D inpercent by weight based on the total weight of monomers (A) and (B) andrepresented by the equiation

        about 34√X <]D < about 150√X                            

wherein X represents the percent by weight of monomer (A) based on thetotal weight of monomers (A) and (B).
 29. The method of claim 28,wherein the polymerization is carried out in the presence of a radicalinitiator.
 30. The method of claim 28, wherein the polymerization iscarried out with said monomer mixture and organic liquid in suspensionin an aqueous medium.
 31. The method of claim 28, wherein said monomermixture consists essentially of: (a) at least one monomer selected fromthe group consisting of ethylene glycol dimethacrylate, divinylbenzenesand divinylpyridines, (b) at least one monomer selected from the groupconsisting of 2-vinylimidazole, N-vinyl-2-methylimidazole and4-vinylpyridine and (c) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes, 2-vinylpyridine,2-methyl-5-vinylpyridine, methyl methacrylate, methyl acrylate and1,3-butadiene and said organic liquid is selected from the groupconsisting of benzene, toluene, xylenes, ethylbenzene, diethyl benzenes,tetraline, butanols, pentanols, cyclohexanol, octanols, ethyl acetate,butyl acetates, ethyl propionate, butyl propionates, butyl adipates,methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate,methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone,chlorobenzene and o-dichlorobenzene.
 32. The method of claim 28, whereinsaid monomer mixture consists essentially of: (a) at least one monomerselected from the group consisting of ethylene glycol dimethacrylate,divinylbenzenes, trivinylbenzenes and divinylpyridines, (b) at least onemonomer selected from the group consisting of 2-vinylpyridine and2-methyl-5-vinylpyridine and (c) at least one monomer selected from thegroup consisting of styrene, ethylvinylbenzenes, methyl methacrylate,methyl acrylate and 1,3-butadiene and said organic liquid is selectedfrom the group consisting of butanols, pentanols, octanols andcyclohexanol.
 33. The method of claim 28, wherein said monomer mixtureconsists essentially of: (a) at least one monomer selected from thegroup consisting of ethylene glycol dimethacrylate, divinylbenzenes anddivinylpyridines, (b) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes, methyl methacrylate,2-vinylpyridine, 2-methyl-5-vinylpyridine and 1,3-butadiene, and (c) atleast one monomer selected from the group consisting of acrylonitrileand methacrylonitrile and said organic liquid is selected from the groupconsisting of benzene, toluene, xylenes, ethylbenzene, ethyl acetate,methyl propionate, butyl propionates, butyl adipates, methyl benzoate,ethyl benzoate and diethyl phthalate.
 34. The method of claim 28,wherein when acrylonitrile is employed as monomer (c) said organicliquid is selected from the group consisting of propionitrile,n-butyronitrile, nitroethane, nitropropane, methyl ethyl ketone andcyclohexanone.
 35. The method of claim 28, wherein said monomer mixtureconsists essentially of: (a) at least one monomer selected from thegroup consisting of ethylene glycol dimethacrylate, divinylbenzenes anddivinylpyridines, (b) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes and 2-methyl-5-vinylpyridineand (c) N-vinylcarbazole and said organic liquid is selected from thegroup consisting of acetone, methyl ethyl ketone, methyl isobutylketone, dimethyl tetrahydrofuran, ethyl acetate and methyl propionate.36. The method of claim 28, wherein said monomer mixture consistsessentially of: (a) at least one monomer selected from the groupconsisting of ethylene glycol dimethacrylate, divinylbenzenes anddivinylpyridines, (b) at least one monomer selected from the groupconsisting of styrene, ethylvinylbenzenes, methyl methacrylate and2-vinylpyridine and (c) N-vinylpyrrolidone and said organic liquid isselected from the group consisting of ethyl acetate, butyl propionates,benzyl acetate, diisopropyl ketone, benzene, toluene, ethylbenzene andtetraline.
 37. The method of claim 28, wherein said monomer mixtureconsists essentially of: (a) at least one monomer selected from thegroup consisting of divinylbenzene and N,N'-ethylene acrylamide, (b) atleast one monomer selected from the group consisting of styrene,ethylvinylbenzenes, methyl methacrylate and methyl acrylate and (c)acrylamide and said organic liquid is selected from the group consistingof benzene, toluene, ethylbenzene, xylenes, tetraline, butyl acetates,ethyl propionate and methyl benzoate.